The world's cities are about to get a lot busier. Today, more than 50% of the global population lives in cities; by 2050, that figure will have risen to 75%.
This mass migration to cities could result in crowded streets rife with air pollution, traffic accidents and congestion. Or it could see a boom in clean, compact urban centres with safe, healthy communities. The way the world's cities operate in the future will be shaped by how they are designed and developed now.
Many cities face major hurdles when it comes to traffic safety, air quality, and physical inactivity. As urban populations swell, these challenges will become all the more pressing.
More than 90% of road traffic deaths occur in middle- and low-income countries – precisely where urbanisation is accelerating most rapidly. About 1.3 million people die prematurely every year due to urban air pollution, a figure that will increase as more cars take to the road. Already, 1.2 million people die and up to 50 million are injured in traffic accidents annually. Nearly half of these incidents occur in cities.
While cities face great challenges, they are also engines of economic growth. It is important city planners work to maintain that economic activity, even as they develop urban designs that are sustainable and good for public health. Smart urban planning can dramatically improve traffic safety, air quality, physical activity in the world's cities.
It all starts with a vision: what kind of cities do we want to live in? How much time do we want to spend commuting, or with our families and friends, or pursuing our favourite activity? Do we want to accept traffic fatalities and injuries as the norm? How important is it for us to live in a healthy environment? For city dwellers, such issues can greatly impact quality of life.
Some planners choose to expand the outer limits of a city as the population grows; the result is urban sprawl. In cities such as Mumbai, Mexico City, Rio de Janeiro, and Istanbul, many people are forced to travel considerable distances to go to work, obtain services, and generally go about their lives. The number of cars on the road goes up with urban sprawl, as does the risk of road accidents. Air pollution gets worse, and quality of life declines.
However, forward-thinking planners can design compact cities that have a positive impact on human health. In areas with small blocks, vehicles make more frequent stops and typically travel at slower speeds. Cities with lower average car speeds and less complex intersections are safer for car passengers and pedestrians alike.
Compact urban design can also encourage physical activity. Dense cities such as Amsterdam, New York, and Copenhagen offer residents more opportunities to cycle or walk. Because more trips can be made without a car, fewer vehicles are on the road. This reduces the risk of traffic crashes and decreases greenhouse gas emissions and other types of air pollution. Finally, denser cities make high-quality public transport much more affordable to build.
That is goods news from a public health perspective. Research from the World Resources Institute's Embarq Centre for Sustainable Transport has shown that well-designed mass transport systems are many times safer than private cars, the typical method of travel in a sprawling city. For example, in Guadalajara, 99% of traffic accidents involve private vehicles (pdf). Only 1% of crashes occur along the Macrobus bus rapid transit (BRT) corridor.
The magnitude of the challenges that cities face calls for new structural solutions. And some cities are making progress on that front. Embarq is working with officials in more than 50 cities across six countries to redesign streets and public spaces, give people better options for getting around, and improve mass transit systems. In Mexico City, for example, Embarq has supported the construction of almost 620 miles of BRT corridors. These transit systems have cut commuting times by nearly 12m hours annually, reduced traffic-related injuries and fatalities by roughly 40%, and eliminated more than 113,000 tons of carbon dioxide emissions a year.
Many of today's booming cities are expanding, which is exacerbating urban challenges. But it need not be so. City planners must focus on smart design, public transport, and creating new opportunities for walking and cycling. Urban communities – and the environment – are depending on it.
Claudia Adriazola is health and road safety programme director at the World Resources Institute.